Wow.
Most games have a very linear difficulty curve. The levels slowly get more difficult as you go along. This one, however, seemed really easy up until level six, until suddenly the levels just got really, really challenging.
I had to watch the walkthrough for the last few, and after watching them I realize that there was no way in hell i would have ever, ever figured those out. Honestly, in most difficult puzzle games, I usually think after watching the walkthrough, "okay, that's cool. I could have probably figured that out." This is the first game where, again, never in a million years.
For that I give you many kudos. Very awesome job creating the most difficult puzzle game I have ever played, and I hope you continue making them.
Okay, what the hell was up with the last level?! REALLY!? How the HELL am I supposed to beat that!?